This application is for a five-year extension of funding for the Diabetic Retinopathy Clinical Research Network (DRCR.net) Network Chair. The DRCR.net is dedicated to support multicenter clinical research of diabetic retinopathy, macular edema and associated conditions through a collaborative network utilizing specialized infrastructure resources that include a Coordination Center and Network Chair's office. The Network's primary goal is to identify, create, conduct, analyze and report high quality clinical tral protocols that lead to a better understanding of diabetic retinopathy, advance its treatment, and improve the lives of individuals with diabetes. The uniqueness of the Network and its efficiencies of scale allow the performance of protocols using money from the NIH, industry, and foundations. These protocols often involve trials that would not be done by industry and would not be feasible with solely NIH funding. These trials include comparative effectiveness studies, new indications of approved drugs, and the testing of new therapies, including Phase I and II clinical trials. The general goals of the DRCR.net over the next 5 year period include 1) continuing to develop protocols in a rapid and efficient manner while maintaining absolute scientific rigor and integrity, 2) continuously identifying and focusing upcoming studies on the most important medical and public health diabetes ophthalmic issues of the day and 3) continuing the legacy of innovative novel approaches to clinical trial design & implementation, network structure, and education. During the next funding cycle, the Network proposes to complete 6-8 protocols that are expected to be in progress at the time the funding period begins, initiate 10-15 new protocols (including 1-2 new major protocols per year) in diabetic retinopathy, diabetic macular edema and associated conditions, continue to expand the DRCR.net by soliciting the participation of new sites, continue to educate the DRCR.net investigators on the principles of clinical research, and mentor selected retina specialists to be leaders in clinical trials with specific reference to diabetic retinopathy.